Triuranium octoxide
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Other names
Uranium(V,VI) oxide
Pitchblende C.I. 77919 | |
Identifiers | |
3D model (
JSmol ) |
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ChemSpider | |
ECHA InfoCard
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100.014.275 |
EC Number |
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PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
U3O8 | |
Molar mass | 842.08 g/mol |
Melting point | 1,150 °C (2,100 °F; 1,420 K) |
Boiling point | decomposes to UO2 at 1,300 °C (2,370 °F; 1,570 K) |
Solubility in other solvents | Insoluble in water;
Soluble in nitric and sulfuric acids. |
Thermochemistry | |
Std molar
entropy (S⦵298) |
282 J·mol−1·K−1[1] |
Std enthalpy of (ΔfH⦵298)formation |
−3575 kJ·mol−1[1] |
Hazards | |
GHS labelling: | |
Danger | |
H300, H330, H373, H411 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Triuranium octoxide (U3O8)[2] is a compound of uranium. It is present as an olive green to black, odorless solid. It is one of the more popular forms of yellowcake and is shipped between mills and refineries in this form.
U3O8 has potential long-term stability in a
Triuranium octoxide is converted to
Solid state structure
The solid is a layered structure where the layers are bridged by oxygen atoms, each layer contains uranium atoms which are in different coordination environments.[citation needed]
Bond valence study
Using a 6Å × 6Å × 6Å box with the uranium atom in the centre, the bond valence calculation was performed for both U1 and U2 in solid. It was found, using the parameters for U(VI), that the calculated oxidation states for U1 and U2 are 5.11 and 5.10. Using the parameters for U(IV), the calculated oxidation states are 5.78 and 5.77 for U1 and U2, respectively. These studies suggests that all the uranium atoms have the same oxidation state, so that the oxidation states are disordered through the lattice.[citation needed]
Other studies have shown evidence that a two U5+ and a single U6+, or other similar combinations, may be a more correct representation.[3]
References
- ^ ISBN 978-0-618-94690-7.
- ^ "triuranium octaoxide". webbook.nist.gov. Retrieved 2022-12-20.
- .